Comprehensive two-dimensional gas chromatography--quadrupole mass spectrometric analysis of drugs.

The use of comprehensive two-dimensional gas chromatography coupled to quadrupole mass spectrometry (GC x GC-qMS) for drug screening is investigated with 77 underivatised drug standards in methanolic solution. The GC x GC-qMS setup involved a reduced mass scan range of 42-235 u and minimum quadrupole sampling time to achieve quadrupole scanning frequency of 19.36 Hz. Only 26% of the drugs investigated gave fair-to-acceptable library matches with full mass scan range commercial libraries. The creation of a new "truncated" library based on the mass spectra of the drug standards in the applied mass scan range of 42-235 u extends the feasibility of the currently adopted GC x GC-qMS approach to higher molecular weight compounds and is investigated with blank blood spiked with drug standards. With the new library, 75% of the drugs yielded matches of at least 90%. The time-of-flight mass spectrometer (TOFMS) is expected to address the limitations of the present GC x GC-qMS setup and a brief comparison between GC x GC-qMS and GC x GC-TOFMS is also provided in this study.